[TASK] Acceptance tests with travis-ci

Set up a basic test system in .travis.yml to run
the login acceptance test with selenium and
phantomjs headless browser in travis-ci.

Change-Id: I944ec6ffcf73e4a138271303dfce8aa7aa121b26
Resolves: #68110
Releases: master
Reviewed-on: https://review.typo3.org/46660


Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>